I would not do new installations with Cat5e spec'd cable, but would pay the premium for up-to-date certified cable, i.e. CAT6,CAT6a or CAT7. The premium is neglectable, and you do not need to worry if you want to upgrade to 10GBit ethernet in 3-4 years from now.

I learned quite a few things. CAT6a is so far only adopted by large enterprises AFAIK. All my equipment is consumer equipment and therefore CAT6(E). When or if CAT6A equipment becomes available cheap is a good question. In the meanwhile I have bandwidth I cannot use since all my (granted, old) machines are CAT6E or plain CAT6.

It would not have worked in my non-insulated, brick building flat however, since there is no hidden room between outer wall and inner wall. So I'm quite satisfied. The CAT6A cable also has a tougher sheath so it wasn't harmed by rough handling during construction, and sports better anti-cross-talk measures. If you can run tubes and pull wire through them, do so. You can then buy cable according to budget. I paid 3-4x the amount I would have paid for regular CAT6 because I knew it would last some 15 years. But they cannot be replaced.